J. Kissel Following the installation of the front-end infrastructure for calibration lines and optical gain compensation for the DELTA L EXTERNAL calibration (see LHO aLOGs 17114, 17179, and ), I've modified the CAL_CS_OVERVIEW.adl MEDM screen, and created newer lower-level screens for the details of the generation of calibration lines and the computation of the optical compensation (i.e. the "gamma" factor). See attached screen shots. Also, for the record I've started to put together documentation of this stuff, check out T1500121. Now that the MEDM interface is established, we'll begin filling out the parameters of the infrastructure, and finally get some calibration lines in the DELTA_L_EXTERNAL spectra. Stay tuned!